Identification and Functional Characterization of Divergent 3’-Phosphate tRNA Ligase From Entamoeba histolytica

Abstract

HSPC117/RtcB, 3’-phosphate tRNA ligase, is a critical enzyme involved in tRNA splicing and maturation. HSPC117/RtcB is also involved in mRNA splicing of some protein-coding genes including XBP-1. Entamoeba histolytica, a protozoan parasite responsible for human amebiasis, possesses two RtcB proteins (EhRtcB1 and 2), but their biological functions remain unknown. Both RtcBs show kinship with mammalian/archaeal type, and all amino acid residues present in the active sites are highly conserved, as suggested by protein alignment and phylogenetic analyses. EhRtcB1 was demonstrated to be localized to the nucleus, while EhRtcB2 was in the cytosol. EhRtcB1, but not EhRtcB2, was required for optimal growth of E. histolytica trophozoites. Both EhRtcB1 (in cooperation with EhArchease) and EhRtcB2 showed RNA ligation activity in vitro. The predominant role of EhRtcB1 in tRNAIle(UAU) processing in vivo was demonstrated in EhRtcB1- and 2-gene silenced strains. Taken together, we have demonstrated the conservation of tRNA splicing and functional diversification of RtcBs in this amoebozoan lineage.

Transfer RNA-Derived Small RNAs in the Pathogenesis of Parasitic Protozoa

“…It has been demonstrated that tRNA splicing and 2’, 3′-cyclic phosphate ligases are conserved in the amoebozoan Entamoeba histolytica , suggesting the possibility of the presence of tRNA intronic circular RNAs [ 66 ]. This anaerobic protozoan parasite is the causative agent of amebiasis in humans, a disease often characterized by diarrhea, but could lead to more severe symptoms such as abscess formation upon invasion of the lungs, liver, or brain [ 67 ].…”

The Consequences of Contaminant miRNAs in Secreted Media Analysis

“…Phosphate And 5'-OH Ligase (Peng, 2021). The ligase binds the two halves together by joining the phosphate in the 5' half's 3' region to the 3' half's 5' hydroxyl, producing a fully connected tRNA (Peng, 2021).…”

“…Phosphate And 5'-OH Ligase (Peng, 2021). The ligase binds the two halves together by joining the phosphate in the 5' half's 3' region to the 3' half's 5' hydroxyl, producing a fully connected tRNA (Peng, 2021). The complex tRNA modifications occur to produce tRNA-amino acid specificity, codonanticodon interactions, and tRNA stability (Hopper, 2013).…”